Combustion chamber with removable flame tubes



Jan. 15, 1957 R. F. DARLING 2,777,291

COMBUSTION CHAMBER WITH REMOVABLE FLAME TUBES Filed May l0, 1952 2Sheets-Sheet l ATTORNEYS Jan. 15, 1957 R. F. DARLING COMBUSTION CHAMBERWITH REMOVABLE FLAME TUBES 2 Sheets-Sheet 2 Filed May 10, 1952 UnitedStates Patent O COMBUSTION CHAMBER WITH REMOVABLE FLAlVIE TUBES RobertFrancis Darling, Monkseaton, England, assigner to The Parsons and MarineEngineering Turbine Research and Development Association, Wallsend,England Application May 10, 1952, Serial No. 287,211

Claims priority, application Great Britain .Iuue 12, 1951 This inventionrelates to combustion chambers particularly, though not exclusively, forgas turbines.

In designing the combustion system for a gas turbine one of the rstquestions that has to be decided is whether to have a single largecombustion chamber or a number of small ones working in parallel, eacharrangment having its own disadvantages. In a single chamber the partsmay be too heavy to be handled conveniently, and in addition, a fuelsprayer of large output gives coarser atomization than a smaller oneWorking at the same fuel supply pressure. This latter difculty cansometimes be overcome by using a cluster of small sprayers in a singlecombustion chamber, but such a cluster is not easy to installsatisfactorily, and there is sometimes a tendency for the sprays tointerfere with one another.

If, on the other hand, several small combustion charnbers are employedin parallel, it becomes diieult to maintain a uniform temperature at theturbine entry, as the quantities of air and/ or fuel supplied to theindividual chambers may not be identical, and in particular,considerable labor and expense is involved in ensuring that the sprayersall give exactly the same fuel iiow at all pressures.

The object of the present invention is to provide a combustion chamberembodying a plurality of removable flame tubes and in which asubstantially uniform temperature can be attained.

The present invention consists in a combustion chamber for a gas turbineor the like having features as set forth in the claims appended hereto.

Referring to the accompanying diagrammatic drawings:

Figure 1 is a vertical longitudinal sectional view of one convenientform of combustion chamber embodying the present invention.

Figure 2 is a sectional plan view of the arrangement shown in Figure 1.

Figure 3 is a cross sectional view on the line III- III of Figure 2.

Figure 4 is a cross-sectional view of a possible alternative form ofthat shown in Figures 1-3.

In carrying the invention into effect according to one convenient formillustrated in Figures 1-3 as applied to a combustion chamber for a gasturbine, a large circular outer casing a is furnished with two pairs ofradial holes d in walls, a detachable domed cover c being fitted to eachhole. Flame tubes e are inserted one through each of the holes d withtheir longitudinal axis at right angles to the longitudinal axis of thecasing, and their inner ends register with holes in a perforated innermember within the chamber. Each cover cis fitted with a fuel sprayer k.The air is introduced at the inlet of the chambers and outlet j is thehot gas outlet.

The detachable covers c may be removed in order to insert or extract theilame tubes e in relation to the hoies in the outer casing a and innermember s.

The air enters the outer casing of the combustion chamber through anopening Thereafter it can follow a number of alternative paths. Most ofit distributes itself between the ilame tubes and passes through thevarious air ports therein to the combustion spaces contained within thellame tubes. From here the combustion gases issue into the common mixingzone h, and thence through the combustion chamber outlet. A portion ofthe air, however, may pass from the outer casing through the adjustablevalve n direct into the mixing space h where it mixes with thecombustion gases and passes with them to a combustion chamber outlet j.Opening of the adjustable valve n allows more air to pass through it andthereby reduces the amount of air passing through the llame tubes. Inthis way the operation of the valve n enables the air flow through thearne tubes and hence the air/ fuel ratio in the flame zone to becontrolled.

By this means the gas issuing from any one llame tube outlet is causedto mix with gases from the other ame tubes and also with any air whichmay have been allowed to pass the damper n. This results in asubstantially uniform temperature distribution at the outlet of thechamber, even when fuel is supplied to some of the flame tubes but notothers.

I claim:

l. A combustion chamber comprising an outer cylindrical member, an innermember co-axial with the outer one, both inner and outer members beingperforated in such a way that flame tubes can be inserted through theperforations in the outer member and lit into the perforations in theinner member, arne tubes tting into the said perforations in the innermember and extending so that the longitudinal axes of these tubes lie atright angles to the longitudinal axis of the outer member, removableapertured covers fitting the perforations in the outer member andsprayers inserted through the apertures in the said covers.

2. A combustion chamber as claimed in claim 1, the said inner memberhaving also a further perforation providing for air flow from the spacewithin the outer tube into the inner member, and comprising also anadjustable valve member in the last said perforation for regulating flowtherethrough.

References Cited in the le of this patent UNITED STATES PATENTS 520,481Davis May 29, 1894 1,380,997 Metcalfe June 7, 1921 1,568,479 SownitzaJan. 5, 1926 2,119,580 Hardgrove June 7, 1938 2,140,785 Cone Dec. 20,1938 2,332,866 Mller Oct. 26, 1943 2,430,344 Kemp Nov. 4, 1947 2,565,843Dennison Aug. 28, 1951 2,604,797 Peregrine July 29, 1952 2,609,040Aronson Sept. 2, 1952 2,654,219 Zaba Oct. 6, 1953 2,715,816 Thorn et alAug. 23, 1955 FOREIGN PATENTS 449,129 Great Britain June 22, 1936

